Summary

Passive immunotherapy with therapeutic antibodies is one of the most promising treatments for Ebola virus infection. Despite disappointing initial results using single monoclonal antibodies (mAbs) (1), successful post-exposure protection in nonhuman primate models of Ebola virus infection was eventually achieved using “designer polyclonals” that mixed individual mAbs (2). The efficacy of an optimized three-mAb cocktail (ZMapp) in protecting nonhuman primates (3) was the basis of its compassionate use and clinical evaluation during the 2014 to 2015 West African Ebola virus outbreaks. The limited protective breadth of available antibodies against specific ebolavirus species, however, raises concerns with respect to a general preparedness for filovirus outbreaks (4). On page 350 of this issue, Wec et al. (5) describe exploiting the powerful nature of bispecific antibodies (bsAbs)—the ability to recognize two different proteins or epitopes with a single antibody—to block entry of multiple ebolavirus species into cells. This may lead to the development of antiviral immunotherapy with cross-filovirus activity.